Thermostatic control device



Marsh 13., i928. ,562,556

' J. C. VVOODSON ,THERMOSTATIC CONTROL DEVICE File@ June 23. 1926 2 sheets-Sheet l INVENTOR James C. Woodsm,

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wIlTNEssEs ATTORNEY March 13, 1928. 1,662,556

J. c. wooDsoN THERMOSTATIC CONTROL DEVICE Filed June 25. 1926 2 Sheets-Sheet 2 WITNESSES: INVENTOR l l James CWoodso/v.

Patented Mar. '13, 1928.

UNITED 'STATES PATENT OFFICE.

I l TAXES C. WOODSON, 0F EAST IITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 ATES'JIN'G- HOUSE ELECTRIC b IANUACTURING COMPANY, A CORPORATION -OF PENNSYL- VAN IA.

TBERIOSTATIC CONTROL DEVICE.

Application lled June 23, 1926. Serial No. 117,924.

My invention relates to electrically-heated devices and particularly to the thermostatic control devices therefor.

An object of my invention is to provide a thermostat for an electrically-heated device that shall be ,effective to control the temperature oi a body to be heated over a relatively wide range of temperatures.

Another object of my invention is to provide a thermostat for an electrically-heated device that shall be operative at a relatively low temperature and that shal1`be efective to control the temperature of a body to be heated over a relatively wide range of high temperatures.

Another object of my invention is to provide a thermostat for an electrically-heated device that shall have means associated therewith lor controlling the rate of heat conduction thereto from a body to be heated, whereby the thermostat will be operable to control lthe temperature of said body over a wide range of temperatures.

,In practicing my invention, l provide a thermo-responsive device for controlling the 'energization of electric resistors which are employed for heating a body ci material. The thermostat is disposed in thermal rela tion with the body to be heated and means are provided for controlling the rate oi heat conduction thereto from the body whereby an even tempcrature thereoi may he main tained., o

ln the accompanying drawings,

Figure 1 is a view, in vertical section, oil an electrically-heated device in which is provided one 'lorm of a thermo-responsive devifce for controlling the temperature there e Fig. 2 is a view, in vertical section, of the device illustrated in Fig. 1 in which a modiu lied term oi' the thermo-responsive device is employed.

Fig. 3 is an end view of the thermo-re-z sponsive device employed in Fig. 2; and

Fig. 4: is a view, in vertical section, of the electrically-heated device illustrated in Figs., 1 and 2, in which vthe thermo-responsive device is mounted at the bottom of the device to be heated. c

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the drawings, an electrically-heated device 11, such as a solder pot, comprises a casing 12, refractory walls 13, heating units 14 and 'a vessel 15.

Referring more particularly to Fig. 1 of A thermc-responsive device 16 is mounted on a lflange 17 of the vessel 15, and an adjustable heat storage mass 18 is mounted, in thermal relation therewith, at the underside thereof.

The walls 1-3 may be made of any suitable electric-insulating material known in the art and the vessel 15 may be madeof any suitable metal, such as nickel-steel or other metal which will withstand high temperatures without excessive oxidation. As a specific construction lof electric heating device 11 forms no particular part of my invention, it is not believed necessary to describe it further in detail.

In Fige 2, I have illustrated a modified form oil the thermo-responsive device 16. In this particular embodiment oi my invention, the device 16 is secured to a movable member 19 which is free to slide horizontally within a dovetailed groove 21 located in the flange 17. A locking means 22, which comprises a holt member 23 and nut 2d, is provided for maintaining the thermoresponsive device 16 in any predetermined position. v

@onductors 25 and 26 are provided for the device 16, whereby a control circuit (not show/'ni for the heatingl units 1dmay he controlled in accordance with the 'temperature at which material located within the vessel 15 is to be maintained.

Ey moving the member 19 inwardly' towards the member 15, the thermoeresponsive device 16 will he subjected to a 'temperature which approaches the temperature oi the body to he heated within the vessel The closer the thermostat 16 is to the material to he heated, the lower will be the temperature of the material contained in the vessel 15, because the operating temperature oil the thermoresponsive device 16 will he attained at a lower temperature of the material 'than if the member 19 were moved farther away from the vessel 15.

Likewise, in Fig. 1 of the drawings, ir the member 18 is moved inwardly towards the vessel, 15, by means of an adjusting screw 27, the thermo-responsive member 16 will be subjected to a tem erature which approaches that 'of thabo y of material to be heated. Conversely, if the member 18 is moved outwardly away from the vessel 15, the thermo-responsive device 16 will be subjected to a lower temperature, with the result that the material to be heated within the container will have attained a higher temperature betore an operating temperature ot the thermostat 16 occurs.

1llfhen the operating temperature ot the member 16 is attained, the member 28 ot the lll thermo-responsive device 16 is disengaged trom the contact members 29, whereby the heating units 14 will be 'deenergized ln lllig. 4: of the drawings, the thermo-responsive device 16 is mounted in an aperture 31 in the bottom wall oi' the electricallyheated device 11. Ain adjusting screw 32 is provided tor moving the thermo-responsive member 16 vertically towards or away from the heating unit 14. lt the device 16 is located in close proximity to the heating units 1dthe device 16 will operate to deenergize the heating units 1li before a very high temperature is attained within the material located in the vessel 15. 1f the device 16 is located at a relatively large distance below the heating unit 14C, the temperature to which the device 16 is subjected will, consequently, be lower and any material to be heated in the vessel 15 will be heated to a much higher temperature before the member 16 has attained a temperature sucient to separate the contact members 29. Y

While l do not wish to'be limited to a particular term ot the thermostat vto be employed in my device, l propose to use one which is described and claimed in a U, S, patent to il. A.. Spencer, No, 1,148,210,

The operation ont my device is best illustrated by reterring to-Figs. 1, 2 and d ot the drawings. The operation ot the thermo-responsive device '16 is dependent upon the temperature to which it is subjected. llt the member 16 ot lFig. 1 is located in close proximity to the wall ot the vessel 15, any material which is maintained vat a .certain temperature therewithin will transmit heat thereto, The member 16 may be ot any suitable material, such as copper or nickel and which has a high lheat-storage capacity, The portion ot the vessel 15 directly below the thermo-responsive device 16 may be made ot such thickness that the heat trom the member 16 will he conducted readily thereto,

llt is evident :trom the drawings that, it the member 16 is in close proximit to the walls ot the vessel 15,' it will be maintained at a higher temperature and, obviously, the thermo-responsive device 16 will also be subjected to the higher temperatures, Sincev the .device 16 is operable at some certain predetermined temperature, the member 18 will conduct more heat trom the body ot the material within the vessel to be heated when it is in close proximity thereto and will, therelore, operate to causethe device 16 to deenergze the heating umts 1a when the matevessel 15 to transmit the re rial within the vessel 1li is at a relatively low temperature, By moving the member 18 away trom the walls ot the vessel 15, the temperature thereof will be in accordance with the temperature ot' the material to be heated, but a much higher temperature will be necessary in themateriacontained in the heat to the member 18 in order to cause the thermo-responsive device 16 to operate to deenergize the heating units 1d'.

uired amount ot When the heating units have beenv deenergized and the member 18 has cooled suii'iciently, 4the device 16 will also follow the drop in temperature and operate to again energize the heating units 14, whereby 'the material will increasev in temperature. By a series of such operations, in which the thermo-responsive device controls the energizing and deenergizing oit the heating units 14s, the material within the vessel 15 will be maintained at a relatively uniform temperature. i j

, rlhe operation ot the device illustrated in Fig. 2 is substantially the same, in principle, as the operation of the device illustrated in F ig. 1, eXceptthat the thermostat 16 is moved away from or towards the walls of the vessel 15 inv accordance with a temperature towbe maintained therein. rlhe device illustrated in Figs. 1, 2 and l ot the drawings may be employed for maintaining lowmelting-point materials, such as solder or babbitt, in a molten state.

Various modificati-ons may be made in the device embodying my invention without departing from the vspirit and scope thereof. ll desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art and the appended claims,

l claim as my invention:

1, lln an electric heating device, the com bination with a vessel :tor containing a body ot material to be heated, electric heating means disposed in thermal conductive relation thereto, a thermostat for controlling the 'energization ot said heating means, ot means tor varying the amount of heat conveyed to said thermostat trom the material to be heated in accordance with a predetermined temperature to be maintained in said ma"- ierial, v

2 1in an electric heating device, the com bination with a vessel tor containing a body ot material to be heated, electric heating means disposed in thermal conductive relation thereto, thermo-responsive means tor controllin said heating means, ot means tor contro ling the rate' of heat conduction to said thermo-responsive device trom said body ot material in accordance with a predetermined temperature to be maintained therein,

6.. lin an electric heating device, the combination with a vessel for containing mate- `to the material to be heated in accordance with a predetermined temperature at which said material is to be maintained.

4. In an electric heating device, the combination Awith a vessel for containing a body of material to be heated, elect-ric heating means disposed in thermal conductive relation thereto, a thermostat for controlling the energization of said .heating means, of means for regulating the amount of heat conveyed to said thermostat from said material to be heated, comprising a mass of heat-storage material in heat-conductive relation to the material to be heated, and adjusting means for moving said thermostat relatively to said mass in accordance with a predetermined temperature to be maintained in said material.

5. In an electric heating device,.the comhination with a container, electric heating units for heating material therein, a thermoresponsive device for controlling said heating units, said device being disposed in thermal relation with said container, of means for regulating the amount of heat conducted to said thermo-responsive device.

6. In an electric heating device, the combination with a container, electric heating units forheating material in said container, a thermo-responsive device for controlling said heating units, said device being disposed in thermal relation to said container, of means for controlling the temperature to which said thermo-responsive device is subjected comprising a mass of material having a high heat-storage capacity and thermal conductivity, and means for changing the position of said mass with respect to said thermo-responsive device.

7. In an electric heating device, the combination with a container, electric heating units therefor for heating material contained therein, a thermo-responsive device for controlling said heating units in accordance with a predetermined temperature to be maintained in said material, said device being located out of direct thermal relation with said material, of means for conducting heat from said material to said thermo-responsive device comprising a mass of heatstorage material and means for moving said mass relatively to said material and said thermo-responsive device.

In testimony whereof, I have hereunto subscribed my name this 17 day of June, 1926.

J AMES C. WOODSON. 

